1. Field of the Invention
The present invention relates to an apparatus and a method for receiving system information of a base station in a mobile communication terminal. More particularly, the present invention relates to an apparatus and a method for receiving changing system information of a base station in a mobile communication terminal.
2. Description of the Related Art
When accessing a new cell during any one of an initial access, a cell selection, a cell reselection, or a handover, a terminal of a wireless communication system should receive system information of a cell to be accessed. For example, in the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard, system information includes a Master Information Block (MIB), and System Information Blocks (SIBs) 1˜N. A base station performs scheduling on each of the MIB and SIB1 on a transmission basis and transmits the same, and performs scheduling on SIB2˜SIBN on a transmission basis called System Information (SI) and transmits the same.
A terminal determines information for receiving SIBs using an MIB, determines scheduling information of SI using SIB1, and determines system information change section information and paging message reception information using SIB2.
The base station may change SI as indicated in system information change section information transmitted to the terminal via SIB2 as illustrated in FIG. 1.
FIG. 1 illustrates a system information change section of a conventional wireless communication system.
As illustrated in FIG. 1, a base station transmits an MIB, and SIB1˜SIBN according to each scheduling information during an N-th system information change section 100. If system information changes, the base station informs a terminal of the system information change through a paging message during the N-th system information change section 100.
After that, the base station transmits changed MIB′, and SIB′1˜SIB′N according to each scheduling information during an (N+1)-th system information change section 110.
To be registered in a cell, a terminal requires essential system information of the cell. For example, in a case where the terminal is to be registered in a cell that uses an LTE technique, the terminal should obtain an MIB, SIB1, and SIB2, which are essential system information of the cell. However, when system information changes before the terminal receives SIB2, the terminal cannot receive the essential system information of the cell. That is, the terminal determines system information change section information and information for receiving a paging message using SIB2. Accordingly, the terminal cannot recognize a system information change section until SIB2 is received, and cannot receive a paging message.
When system information changes before the terminal receives SIB2, the terminal cannot recognize that the system information has changed, and accordingly, the terminal tries to receive SI using scheduling information obtained through SIB1 before the system information changes. Therefore, the terminal cannot receive SI. More particularly, in the case where the terminal cannot obtain SIB, which is essential system information of a cell, the terminal may designate a relevant cell as a barred cell.